November 12, 2009 3:30 AM PST
I am assuming you are talking about the Kawasaki Vulcan Classic 1999 listed in your profile.
I am no expert on Kawasaki, but I believe the sound you are hearing is the relay in the junction box, which most likely means it is working.
Sounds to me like you either have a bad starter solenoid or a bad starter.
To do a quick test... turn the key on and use a screwdriver to jump across the starter solenoid (the two big posts with the heavy-duty cables). If the bike starts the solenoid is bad, if it doesn't, its the starter.
Sorry, but I don't know the Kawasaki Vulcan that well, so I can't tell you where the starter solenoid is off the top of my head.